The Black Zone
The Black Zone is a little like Chaos's equivalent of the Golden Circle,
or, rather, it would be if Chaos were even remotely Euclidean.
Basically the Black Zone is the set of "nearest" shadows to the Courts
themselves, where "nearest" is a little ambiguous. Perhaps the best
definition is those shadows most used by the Lords of Chaos, though some
would argue they are the shadows most "like" Chaos, whatever that
means. For the politically minded, the Black Zone consists of those
shadows tightly under the sphere of influence of one House or
another.
The barriers between shadows are thin in the black zone and can be
shaped by some of the lesser denizens of Chaos -- called shadowmasters
-- who lack the power over shadow that mastery of the Logrus grants.
All of the great houses and many of the minor houses incorporate shadows
of the Black Zone into their Ancestral Ways.
[more to come]